Oral Cancer News
Compiled by The Oral Cancer Foundation

lung cancer

February 24, 2012 (Palm Springs, California) — Cancer patients who smoke experience more severe symptoms than nonsmoking cancer patients and are also at greater risk of misusing opioids, a new study shows.

“Our findings show a profile of higher levels of physical symptoms (pain, fatigue, poor appetite, and insomnia) and psychological symptoms (depression and anxiety) among smokers than non-smokers,” report Diane Novy, PhD, from the Pain Management Center at the University of Texas MD Anderson Cancer Center in Houston, Texas, and colleagues.

The findings underscore the importance of smoking cessation for this patient population, she told Medscape Medical News, even though it’s unclear if there is a causal effect.

“We don’t know the cause. They may smoke more because of the pain,” she said in an interview. However, studies also show that smoking has been known to increase certain types of pain such as back pain, and nerve pain, she added. “If we can motivate them to stop smoking, I think they’re better off.”

The findings were presented here at the American Academy of Pain Medicine (AAPM) 28th Annual Meeting.

Pain, Fatigue, Insomnia

The study included 486 cancer patients (52% female), with a mean age of 55 years, who were referred to the Pain Management Center for uncontrolled pain. Ninety-four patients were smokers, and the rest (n = 356), classified as nonsmokers, were former smokers or never-smokers. The patients were diagnosed with a wide range of cancers, the most common being gastrointestinal (18.5%), followed by hematologic (15%) and head and neck cancer (14.6%).

The most common cancer among the smokers was head and neck cancer (22.3% vs 12.8% in nonsmokers), and the most common cancer in nonsmokers was gastrointestinal (19.9% vs 12.8% in smokers). Lung cancer was slightly less common among smokers than nonsmokers (10.6% vs 11.5%).

As part of their intake, patients completed the Edmonton Symptom Assessment Scale (ESAS) and the Screener and Opioid Assessment for Patients with Pain (SOAPP).

The ESAS showed that pain, fatigue, insomnia, appetite, depression, and anxiety were all statistically significantly worse in smokers than nonsmokers.

Specifically, on a scale of 0 (no symptoms) to 10, smokers reported the following:

In addition, the SOAPP suggested that smokers were at greater risk for opioid misuse than were nonsmokers. Smokers reported more frequent mood swings than nonsmokers (26.6% vs 12.5%; P = .002) and were more likely to admit to occasional use of medication in a manner other than how it was prescribed (39.4% vs 19.6%; P < .001), occasional use of illegal drugs in the past 5 years (13.8% vs 2.6%; P < .001), and past legal problems or arrest (25.5% vs 8.2%; P < .001).

Further, among the smokers, 51% reported that they smoke within an hour of waking — an indication of higher risk for opioid misuse compared with smokers who delay their first cigarette.

Taken together, the findings point to the importance of extra caution when managing pain in cancer patients, said Dr. Novy.

“With cancer patients, opioids will always be the mainstay of treatment,” she said. With smokers, “we might change the route of delivery, so it might be a fentanyl patch that the patient can’t misuse, or it might be an opioid that does not have as much addiction potential like methadone, or maybe nerve blocks or other procedures.”

Smoking cessation should also be emphasized, she added. “When we work with patients and we’re able to say smokers seem to experience more pain and more of a symptom burden… for some patients it is an amazing wake-up call.”

On the basis of her results she suggests a clinical interview that explores a patient’s pain coping mechanisms and smoking triggers could help to inform treatment.

“For example, if expectation of analgesic benefit appeared to be an important smoking motivator, challenging these expectations and increasing coping self-efficacy would be reasonable treatment goals,” she reported.

If future studies confirm that smoking is associated with depression symptoms, treatment of depression would be appropriate.

Bi-Directional Interaction

The study by Dr. Novy and colleagues “makes an important contribution to a small, but rapidly growing scientific literature regarding complex and potentially bi-directional interactions between pain and smoking,” commented Joseph W. Ditre, PhD, a clinical psychologist at Texas A & M University in College Station.

“There is growing empirical and clinical interest in purported associations between tobacco smoking and the aggravation of cancer symptoms and treatment side effects, such as pain,” said Dr. Ditre, who recently published findings very similar to those of the current study.

“The current findings are highly consistent with the results of our 2011 study, which showed that continued smoking despite a cancer diagnosis was associated with greater pain severity and interference from pain,” he told Medscape Medical News.

“Some researchers have suggested that other factors (eg, depression) may be responsible for observed relations between smoking and increased pain,” he noted. “Thus, it would be interesting to know whether the current findings remain significant after accounting for sociodemographic, disease-specific, and psychiatric factors. Also, to get a better sense of whether continued smoking may increase pain and functional impairment in a causal fashion, future research should investigate longitudinal relations between continued smoking, smoking abstinence, and pain-related outcomes among persons with cancer.”

He said he agreed with Dr. Novy that smoking cessation should be emphasized in this population.

“Interestingly, our 2011 study showed a negative correlation between pain ratings and number of years since quitting smoking, suggesting that quitting smoking may confer benefit with respect to pain reporting,” he told Medscape Medical News. “Conversely, there is some question as to whether abstaining from smoking may increase pain in the short term (perhaps via removal of a preferred coping strategy, or via direct neurobiological processes).

“That said, smoking cessation is clearly indicated for persons with cancer, not just because smoking may increase pain, but because persistent smoking has been associated with impaired healing, reduced treatment efficacy, and increased risk for developing a second primary cancer,” Dr. Ditre added. “Thus, the advantages of quitting smoking likely greatly outweigh potential disadvantages, especially with respect to cancer-related outcomes.”

The study was supported by funding from the American Cancer Society and the National Institute on Drug Abuse. Dr. Novy has disclosed no relevant financial relationships. Dr. Ditre and his coauthors have disclosed no relevant financial relationships.

This news story was resourced by the Oral Cancer Foundation, and vetted for appropriateness and accuracy.

Cancers of the mouth and throat related to oral sex, as well as thyroid, liver and skin cancers are on the rise among older adults, according to new stats released last week from the American Cancer Society.

There was some good news, however. The death rate is down for the well-known major cancers. The society’s Cancer Statistics 2012 report found that overall, cancer deaths dropped by nearly two percent for both men and women from 2004 to 2008.

That may sound paltry, but Len Lichtenfeld, M.D., the society’s deputy chief medical officer, says it is more significant than it seems: Many people avoided even hearing the words “you have cancer” because advances in cancer treatment caught problems early, while still in the pre-cancerous stage, he said.

The report found that death rates were down for all four major cancers — lung, colorectal, breast and prostate. The biggest drop was for lung cancer, which is down almost 40 percent in the number of men dying from the disease, thanks to fewer Americans smoking.

Deaths among women from breast cancer declined 34 percent, mainly because of increases in mammogram screening and a decrease in hormone use for menopause, the ACS report said.

On the other hand, some cancers are increasing, particularly among older Americans.

According to Medscape News , the ACS found that people 55 to 64 years of age had the highest increase in incidence rates for liver and HPV-related oral cancers; people 65 and older also had an increase in incidence rates for melanoma, or skin cancer.

For men with HPV-related oral cancer and women with thyroid cancer, rising incidence rates were highest among people 55 to 64 years of age.

The following cancers are expected to total about 245,000 new cases of the more than 1.6 million total cancer cases projected for 2012, according to the ACS.

Melanoma: More men over 55 and women of all ages are getting the deadliest form of skin cancer. This may be because of increased use of tanning booths, as well as increased awareness and detection of skin cancer. The good news is that two new drugs were approved last year to treat metastatic melanoma.

HPV-related cancers of the back of the tongue, throat and tonsil area (oropharynx cancers): These cancers, caused by the sexually transmitted Human Papillomavirus (HPV), are increasing in part because of the increased practice of oral sex. On the good news side: Oral cancers from tobacco and alcohol use, and not from HPV, have been steadily declining.

Esophageal, pancreatic, liver and kidney: These are on the rise and obesity may play a role, according to the cancer society. Obesity is associated with a substantially increased risk for esophageal cancer due to acid reflux disease. As for liver cancers, half of the cases are among people with chronic hepatitis C.

This news story was resourced by the Oral Cancer Foundation, and vetted for appropriateness and accuracy.

Tobacco companies knew for decades that cigarette smoke was radioactive and potentially carcinogenic but kept that information from the public, according to a new study.

The tobacco industry began investigations into the possible effects of these radioactive particles, identified as polonium-210, on smokers as early as the 1960s, says the study by UCLA researchers who analyzed dozens of previously unexamined industry documents.

“I’ve not seen a document before that’s specifically cited the industry’s own internal research finding that sufficient levels of polonium-210 can cause cancer,” says Matt Myers of the Campaign for Tobacco-Free Kids. He says the study reinforces the need for the U.S. Food and Drug Administration to scrutinize tobacco products. This week, the FDA began requiring tobacco companies to disclose detailed information about new products and changes to existing ones. The study, published in the peer-reviewed journal Nicotine & Tobacco Research, suggests the FDA make removal of the radioative particles from tobacco products a top priority. “We used to think that only the chemicals in the cigarettes were causing lung cancer,” said Hrayr S. Karagueuzian, lead author of the study. Now, Karagueuzian said, the industry’s own research shows that polonium-210, absorbed by tobacco leaves and inhaled by smokers, is dangerous. He said UCLA researchers found that the radioactivity could cause 120 to 138 deaths for every 1,000 regular smokers over a 25-year period. Karagueuzian said tobacco companies have declined techniques that could help eliminate polonium-210 from tobacco because of concern that smokers might lose the “instant nicotine rush” that fuels their addiction. David Sutton, spokesman for Philip Morris USA, the largest U.S. tobacco manufacturer, said the company does not add polonium-210 to its products. He said it’s a “naturally occurring element in the air” and has been widely discussed by the public health community for years. Industry critic Greg Connolly, who directs Harvard University’s Center for Global Tobacco Control, agrees that polonium-210’s risks have long been known. He said the study, however, reinforces the need for the FDA to regulate tobacco companies, adding, “The $64,000 question is: have they changed?”

This news story was resourced by the Oral Cancer Foundation, and vetted for appropriateness and accuracy.

“If we validate that our Hemopurifier is efficient in capturing exosomes, its possible that we could transition towards a human treatment study to evaluate exosome clearance from the entire circulatory system,” he said.

The test will be conducted by the Sarcoma Oncology Center, a nonprofit independent research institute focused on cancer therapy development.

“This clinical histological study is a critical validation step in Aethlon’s Hemopurifier strategy for cancer,” said Dr. Sant Chawla, the trial’s chief investigator. “The concept of ‘subtractive therapy’, eliminating a major mechanism of tumor progression and resistance to drugs, represents a potential breakout solution that needs to be tested in the clinic.”

The trial will involve 25 patients and will cost just under $75,000, Aethlon officials said.

The filtering system works by pumping blood through a cartridge containing 2,800 hollow fibers that are perforated by tiny holes measuring about 250 nanometers.

Plasma and red and white blood cells pass through the holes and return to the circulatory system while exosomes and other larger particles, such as viruses, are trapped.

The Hemopurifier was cleared by U.S. regulators in 2007 for safety testing to counteract bioterrorism agents.

Last year, the company launched a study of the system on hepatitis C patients in India with the Medanta Medicity Institute near New Delhi.

The rate at which Americans die from cancer continues to fall, according to the latest estimates from the American Cancer Society.

As a result, nearly 900,000 cancer deaths were avoided between 1990 and 2007, the group figures. Survival gains have come as mortality rates have declined for some of the most common malignancies, including colorectal cancer, breast cancer in women and prostate cancer.

Still, the ACS estimates there will nearly 1.6 million new cancers diagnosed this year, and about 572,000 deaths from the disease. The incidence of cancers hasn’t budged much for men in recent years, after falling quite a bit during the first half of the last decade. Cancer incidence for women has been falling since 1998.

The report was just published online by CA: A Cancer Journal for Clinicians.

Lung cancer remains the biggest killer for both men and women. All told, about 160,000 people in the U.S. are expected to die from it this year. Starting in 1987, more women have died from lung cancer each year than breast cancer.

One section of the report focuses on a persistent and, in some cases, widening gap in cancer death rates between people with the least education and those with the most. Educational attainment is often used in research as a proxy for socioeconomic status.

American Cancer Society epidemiologist Elizabeth Ward, one of the report’s authors, tells Shots, “People of a lower socioeconomic status are more likely to smoke and less likely to get access to care where they can get screened for early detection.”

Then there’s issue of health coverage, which can make a big difference in treatment. “People with higher income jobs usually work for employers who offer better insurance,” Ward says.

OCF Note. Oral and head and neck cancers are NOT one of the cancers that has declined. They are one of the few that is actually increasing in incidence in the US.

The gap in cancer death rates between college graduates and those who only went to high school is widening, the American Cancer Society reported Friday.

Among men, the least educated died of cancer at rates more than 2 1/2 times that of men with college degrees, the latest data show. In the early 1990s, they died at two times the rate of most-educated men.

For women, the numbers aren’t as complete but suggest a widening gap also. The data, from 2007, compared people between the ages of 25 and 64.

People with college degrees are seeing a significant drop in cancer death rates, while people who have spent less time in school are seeing more modest improvements or sometimes none at all, explained Elizabeth Ward, who oversees research done by the cancer society.

The cancer society estimates there will be nearly 1.6 million new cancer cases in the United States this year, and 571,950 deaths. It also notes that overall cancer death rates have been dropping since the early 1990s, but the decline has been greater for some groups more than others.

Experts believe that the differences have to do with education, how much people earn and where they live, among other factors. Researchers like to use education as a measuring stick because death certificates include that information.

“Just because we’re measuring education doesn’t mean we think education is the direct reason” for the differences among population groups, Ward said.

That said, the cancer death rate connection to education is striking.

For all types of cancer among men, there were about 56 deaths per 100,000 for those with at least 16 years of education compared to 148 deaths per 100,000 for those with no more than 12 years of school.

For women, the rate was 59 per 100,000 for the most educated, and 119 per 100,000 for the least educated.

The gap was most striking when it comes to lung cancer.

People with a high school education or less died at a rate four to five times higher than those with at least four years of college education, the new report said.

More than a third of premature cancer deaths could have been avoided if everyone had a college degree, cancer society officials estimated.

Studies have suggested that less educated people are more likely to do risky things with their health. They are more likely to smoke, drink and overeat, leading to obesity. All those things raise the risk for various cancers.

As for survival after diagnosis, the least-educated are often poor people without good health insurance. Studies have found that people with no health insurance are more likely to be diagnosed when their cancer is advanced stage, and they are also less likely to receive standard treatment.

Research has shown that cancer patients on bisphosphonates are at risk of developing osteonecrosis of the jaw (ONJ) and that those on the intravenous form of the drug are at a higher risk compared with those on the oral drugs.

However, a new study that looked at cancer patients on zoledronic acid (ZOL) and chemotherapy combined with the antiangiogenic agent bevacizumab (BEV) who underwent a dental exam before starting treatment found that none of them developed ONJ (JADA, May 2011, Vol. 142:5, pp. 506-513).

Researchers from the University of Siena in Italy investigated the incidence of and risk factors for ONJ in patients with metastases to the bone from solid tumors who received ZOL and BEV.

Their study included 59 patients (34 with breast cancer and 25 with non-small cell lung cancer [NSCL]) who received 4 mg of ZOL intravenously every four weeks and 15 mg per kg of BEV every three weeks. The median time the participants received ZOL therapy was 18 months, while the median time participants received BEV therapy was 16 months.

The researchers took several measures to reduce the study participants’ risk of developing ONJ, including the following:

Mouth rinses with chlorhexidine and local antibiotic agents were administered before baseline oral hygiene.

Recommendations were made for maintaining good oral hygiene.

Teeth were extracted at least four weeks before starting ZOL and BEV therapy.

Invasive dental procedures were avoided during treatment.

If invasive dental procedures were needed during treatment, ZOL and BEV were readministered after at least four weeks.

All the patients received a dental exam and panoramic x-rays before starting treatment and every three months until the patients died or were lost to follow-up. After a median follow-up period of 19 months, none of the study participants had developed ONJ.

“The number of patients investigated in this study is too low to make meaningful conclusions.”
— Tanja Fehm, MD

“Despite the fact that new and potent antiangiogenic therapies theoretically might enhance the antiangiogenic effects of ZOL on bone tissue, our findings do not indicate a trend of a higher incidence of BRONJ [bisphosphonate-related ONJ] in patients receiving ZOL and BEV,” the authors noted. “Nevertheless, evidence showing that antiangiogenesis is the main underlying mechanism of BRONJ still is lacking.”

They also noted that the preventive dental measures taken before the start of treatment could have contributed to the fact that none of the participants developed ONJ.

After the baseline dental exam, seven of the study participants needed tooth extractions, which were done before they started taking ZOL and BEV.

The participants avoided undergoing other dentoalveolar surgical procedures while they were receiving treatment, probably owing to the baseline preventive dental examination and the follow-up examinations, indicating that a dental exam prior to therapy can minimize the risk of developing ONJ, the authors noted.

“Although further research is needed, the results of our study suggest that ZOL combined with the antiangiogenic agent BEV does not predispose patients with metastases to the bone from breast and NSCL cancer to ONJ if they undergo a baseline dental examination,” they concluded. “Nevertheless, the results of the study must be considered in the context of the follow-up period used in the study and the use of the preventive dental protocol.”

Tanja Fehm, MD, from the department of obstetrics and gynecology at the University of Tübingen in Germany, has done similar research (Gynecologic Oncology, March 2009, Vol. 112:3, pp. 605-609). She told DrBicuspid.com that the incidence of ONJ is low — between 1% and 4% — in metastatic breast cancer patients receiving bisphosphonates.

“Therefore, the number of patients (59) investigated in this study is too low to make meaningful conclusions,” she added. “However, the paper summarizes the preventive measures that can help avoid ONJ.”

James Berenson, MD, from the Institute for Myeloma & Bone Cancer Research has also done similar research (American Journal of Hematology, January 2011, Vol. 86:1, pp. 25-30) and agreed that this study was too small. He also felt the follow-up period was too short for any conclusive results.

Meanwhile, the study authors hope that these results help general dentists, oral surgeons, and oncologists in their efforts to prevent ONJ and identify at-risk patients by means of careful baseline and follow-up dental examinations.

This news story was resourced by the Oral Cancer Foundation, and vetted for appropriateness and accuracy.

A type of smokeless tobacco popular in Sweden called snus is growing in popularity in the United States. While most recognize that it is a safer alternative to cigarettes or older forms of smokeless tobacco, others are concerned that it will attract young people, becoming a steppingstone to cigarettes, says a researcher who spoke this week at the Smokeless Tobacco Summit in Austin, TX.

There is also concern that smokers may use snus in places where they can’t smoke, which will encourage them to keep smoking instead of quitting, says Lois Biener, PhD, Adjunct Professor, Department of Psychology at the University Of Massachusetts – Boston and Senior Research Fellow at the Center for Survey Research, University Of Massachusetts – Boston.

Snus (pronounced snoos) was first introduced in several U.S. test markets in 2006, and has been available nationwide since 2009. It is sold under several brands including Marlboro Snus and Camel Snus. The product is different from other types of smokeless tobacco in several important ways, Dr. Biener says. Snus is manufactured using a process that makes it lower in carcinogens called tobacco-specific nitrosamines. Snus also doesn’t stimulate saliva the way that snuff does and thus doesn’t require spitting. A person using snus puts a small pouch filled with the product between the lip and the gum.

Dr. Biener’s research has shown that the primary group of snus users in the United States is male smokers. “There is very little trial of the product among females and virtually no trial of it among nonsmokers,” she says.

Because snus comes in sweet and fruity flavors, public health officials are concerned that it is catching on with teens. The 2010 Monitoring the Future survey found that the use of smokeless tobacco (including snus) has started to increase significantly after years of declines. The survey found that 13 percent of 10th grade boys and 15.7 percent of 12th grade boys reported using smokeless tobacco in the previous 30 days.

Mixed Findings on Health Effects

Snus has been long been used in Sweden, where its health effects have been studied. “In Sweden, where cigarette smoking among men is low and snus use is high, we see lower levels of lung cancer among men compared with the rest of Europe and the United States,” Dr. Biener said.

One study of the health effects of snus, published in The Lancet in 2007, studied 125,000 Swedish male construction workers who had never smoked, and followed them for 12 to 26 years. The study found that snus use was associated with a slight increased risk of pancreatic cancer, but was not associated with any increased risk of oral cancer or lung cancer; cigarette smoking was significantly associated with all three.

Another study in the same issue of the journal found there was little difference in life expectancy between smokers who quit all tobacco and those who switched to snus. The researchers of that study concluded that snus could produce a net benefit to health if used by hard-core smokers. That study bolstered the argument that switching smokers to snus could reduce the harm caused by cigarettes.

Dr. Biener is conducting interviews with a representative sample of adults in Dallas/Fort Worth and Indianapolis, two early test markets for the product. There is currently no solid data on what proportion of the individuals who try Snus go on to use it regularly, and Dr. Biener hopes to answer this question. She also wants to find out whether regular snus users change their smoking patterns.

Dr. Biener and her colleagues are also looking at the level of nicotine in various snus products. “It’s likely that snus and cigarettes have comparable levels of nicotine and are comparably addictive, although the mode of delivery of the nicotine is different,” she said.

Another concern of snus critics is that using the product along with cigarettes might lead to higher levels of nicotine addiction and make it harder for people to quit smoking, a theory that she says has yet to be studied.

“People have a right to accurate information about these products,” Dr. Biener said. “It’s important that health agencies are upfront about the different level of risk and harm in different tobacco products, so that people don’t end up thinking, ‘One is just as bad as another so I might as well continue to smoke.’ Until there is more information on how people are using snus and what the impact is on their smoking, we can’t make a recommendation about its use.”

Abstract

Background:

Head-and-neck cancer (HNC) is the eighth most common malignancy worldwide. It is often diagnosed late due to a lack of screening methods and overall cure is achieved in <50% of patients. Head-and-neck cancer sufferers often develop a second primary tumour that can affect the entire aero-digestive tract, mostly HNC or lung cancer (LC), making lifelong follow-up necessary.

Methods:

Alveolar breath was collected from 87 volunteers (HNC and LC patients and healthy controls) in a cross-sectional clinical trial. The discriminative power of a tailor-made Nanoscale Artificial Nose (NA-NOSE) based on an array of five gold nanoparticle sensors was tested, using 62 breath samples. The NA-NOSE signals were analysed to detect statistically significant differences between the sub-populations using (i) principal component analysis with ANOVA and Student’s t-test and (ii) support vector machines and cross-validation. The identification of NA-NOSE patterns was supported by comparative analysis of the chemical composition of the breath through gas chromatography in conjunction with mass spectrometry (GC–MS), using 40 breath samples.

Results:

The NA-NOSE could clearly distinguish between (i) HNC patients and healthy controls, (ii) LC patients and healthy controls, and (iii) HNC and LC patients. The GC–MS analysis showed statistically significant differences in the chemical composition of the breath of the three groups.

Conclusion:

The presented results could lead to the development of a cost-effective, fast, and reliable method for the differential diagnosis of HNC that is based on breath testing with an NA-NOSE, with a future potential as screening tool.

At 68, John Casterline has beaten advanced-stage lung cancer, prostate cancer and throat cancer. Last month, he finished radiation

treatments. Just one week ago, his doctors pronounced him cancer-free.

So what is he doing to celebrate?

Forget Disney World. Starting April 28, this Orlando retiree will be hiking 2,650 miles, from Canada to Mexico, along the Pacific Crest Trail — a route that will climb above 13,000 feet elevation and require him to average 20 miles a day.

“I expect that I will experience weather that is too cold, too hot, too wet, too dry and too perfect,” he wrote in his journal a year ago, when he began training seriously for the hike. “I will encounter rattle snakes, bears, and maybe even mountain lions. … The mosquitoes will be horrendous at times, the hills steep, the rocks sharp, the trail blocked, the wind very strong. [Sleep will be] occasionally fitful and I’ll be carrying a backpack with 30-plus pounds.”

But if you have to ask why he’s doing it, he wrote, you wouldn’t understand.

It is not simply that he hopes to raise $26,500 for the dramatically underfunded battle against lung cancer, a disease expected to claim the lives of 160,000 Americans this year — more than colon, breast and prostate cancers combined.

Nor is it about creating some kind of legacy. Though followers can read his ongoing exploits on lungcancerhike.org, the website is intended to give fellow cancer survivors hope — and to collect donations for the American Lung Association — not to brag.

“John is the guy you want with you in a foxhole,” said Eric Gray, an executive director at the American Lung Association of Florida. “He’s the guy who makes you believe anything is possible.”

Casterline is a favorite at Orlando lung-cancer support-group meetings, and Gray often uses him as a beacon of hope when counseling the newly diagnosed.

“In years past, there hasn’t been a lot to say to people other than, ‘I’m so sorry,’ ” Gray said. But now I can say, ‘Let me tell you about this guy who had Stage 4 lung cancer and this remarkable thing he’s doing …”

Casterline was diagnosed in August 2006, a week after he retired from 21 years working for 7-Eleven preceded by 21 years in the Navy. He had quit smoking seven years earlier — 1999, the same year he took up backpacking at the urging of his eldest son. By the time the disease was detected, it was so far advanced he was given a 3.5 percent chance of surviving the next five years.

“You go through these stages of grief,” he said. “For two or three days, I figured I wouldn’t make it a year.”

It may have been the only time his relentless spirit waned, and even then it didn’t last long. He researched exhaustively, interviewed doctors at five hospitals — including Memorial Sloan-Kettering in his birth state of New York — and ultimately selected M.D. Anderson Cancer Center Orlando. He went through surgery, chemotherapy and more than one round of radiation, and by February 2007 he was officially cancer-free.

That lasted a blissful 3 1/2 years, until he developed prostate cancer. He had just finished surgery for that in November last year when, one month later, doctors discovered the earliest stage of throat cancer.

“He exercised all through chemotherapy and radiation,” said Dr. Jennifer Tseng, his medical oncologist, who counts herself a fan. “Probably the only time he didn’t exercise is when he was in the hospital after surgery. And even then, he was back on his feet in no time. He’s got an amazing spirit and willpower.”

The average person undergoing radiation would still be trying to eat solid food at this point, she said. Casterline, who began competing in marathons 10 years ago, has been out hiking 14 miles a day wearing a 35-pound backpack. Within the past week, all three of his doctors have given their blessing to the upcoming hike.

In fact, in some ways, Casterline’s wife of 41 years, Sue, has been the toughest sell.

“When he first told me about this trip, I thought, ‘You’re out of your mind,’ ” she admits. “It was just surreal. But he’s a force of nature, and he’s going to do what he’s going to do. I mean, I can’t stop him.”

She did, however, make him update his will.

As she says this, the family room has turned into a staging area with 13 cardboard boxes of food due to be shipped to various post offices near the Pacific Crest Trail. Those are for the times when the nearest store is 20 miles away. Casterline has the spots numbered on spreadsheets that detail his mileage, route-elevation changes, meet-ups with his wife and two grown sons, and notations on the hazards du jour.

“Water supply contaminated — dead rodents,” he notes for Day 5, a 20-mile stretch through the scrub oak and chaparral of Southern California. “Poison oak about mile 105.”

His gear has been weighed to the nearest tenth of an ounce. All his clothing comes in at 2.56 pounds. His tent, sleeping bag, backpack, ground cover and pad: 7.66 pounds. Total, with cooking and hygiene supplies, medications, emergency whistle, duct tape, bug repellent, iodine tablets, reading glasses and playing cards: 15.97. It’s the food and water that will add an additional 20 or so pounds. Plus there’s the 1-pound ice axe he can ditch after the halfway point.

He has coaxed sponsorships from Nestlé, which owns PowerBar energy products, and Mango International, which sells a small solar panel to recharge his iPhone. He’ll also carry a pocketknife and perhaps a 6-ounce Kindle reader. But he’s still on the fence over a distress signal that alerts rescue workers you need to be airlifted to a hospital.

“It’s 8 to 10 ounces,” he said, frowning.

Though Casterline feigns fearlessness most of the time, he admits one enormous worry: failure.

“I’m very determined, mentally and physically, and I know I’ve already been tested pretty hard,” he said. “But that’s one of my greatest fears: that I won’t make it.”

On bad days — and there will be bad days — he will remember to look at the names his granddaughter has printed on his backpack in ink. “Alysan F.,” “Judy C.” and “William R.,” they read. There are 100 names in all: lung-cancer patients or their loved ones. Some he has only met online. If not for himself, then at least for them, he must try to persevere.

No one is betting against him.

“Short of getting eaten by a bear,” his wife said, “he’s going to do it.”